import requests

url = 'https://www.pearvideo.com/videoStatus.jsp?contId=1275466&mrd=0.7572545185732078'

refer = 'https://www.pearvideo.com/video_1275466'

head = {
    'Referer':refer
}

res = requests.get(url, headers=head)
'https://video.pearvideo.com/mp4/short/20180207/cont-1275466-11551669-hd.mp4'
'https://video.pearvideo.com/mp4/short/20180207/1691425607968-11551669-hd.mp4'

data = res.json()

video = data['videoInfo']['videos']['srcUrl']
old = data['systemTime']
new = 'cont-'+refer.split('_')[1]

url1 = video.replace(old,new)
res1 = requests.get(url1)

with open('2.mp4','wb') as f:
    f.write(res1.content)